Semiconductor devices, such as IC devices and LSI circuit devices are manufactured in a clean room because semiconductor devices requires utmost elimination of dust particles. Therefore, packaging materials for packaging clothing and such to be worn by persons participating in manufacturing semiconductor devices must be free from dust particles and other contaminants. Accordingly, packaging materials to be used in a clean environment are produced in a clean room and washed with ultrapure water. Preparation of such clean packaging materials needs cleaning means for cleaning packaging materials produced in a clean room with ultrapure water, which requires complicated apparatuses and increases the manufacturing cost. Furthermore, the cleanliness of articles packaged in packaging materials is dependent on the uncertain degree of cleaning of the packaging materials with ultrapure water.